The married are more satisfied [...] suggesting a causal effect at all stages of the marriage, from pre-nuptual bliss to marriages of long-duration

How’s Life at Home? New Evidence on Marriage and the Set Point for Happiness. Shawn Grover, John F. Helliwell. Journal of Happiness Studies, https://link.springer.com/article/10.1007/s10902-017-9941-3

Abstract: Subjective well-being research has often found that marriage is positively correlated with well-being. Some have argued that this correlation may be result of happier people being more likely to marry. Others have presented evidence suggesting that the well-being benefits of marriage are short-lasting. Using data from the British Household Panel Survey, we control individual pre-marital well-being levels and find that the married are still more satisfied, suggesting a causal effect at all stages of the marriage, from pre-nuptual bliss to marriages of long-duration. Using new data from the United Kingdom’s Annual Population Survey, we find that the married have a less deep U-shape in life satisfaction across age groups than do the unmarried, indicating that marriage may help ease the causes of the mid-life dip in life satisfaction and that the benefits of marriage are unlikely to be short-lived. We explore friendship as a mechanism which could help explain a causal relationship between marriage and life satisfaction, and find that well-being effects of marriage are about twice as large for those whose spouse is also their best friend.